Most teams’ pitchers and catchers will report this weekend, with position players a few days behind them. That means the sounds of spring also are here: the crack of the bat, the pop of the glove … the wailing of players who tweak a hamstring.

Unfortunately, injuries are as big a part of camp as position battles, rising rookies and three-inning outings (and nine holes of golf) from veteran starting pitchers. Just think back to last year at this time when the St. Louis Cardinals learned they would have to play the 2011 season without co-ace Adam Wainwright, whose injured elbow required Tommy John surgery.

Things obviously turned out OK for the Cardinals, but several contenders will open camp—and, in some cases, the regular season—without key contributors.

Four such instances:

Philadelphia Phillies

Still sore: 1B Ryan Howard, who had surgery in October to repair a ruptured Achilles’ tendon

Recovery time: The original estimate called for Howard to miss 5-6 months, and it appears he remains on that timetable. Late last month, manager Charlie Manuel told The Philadelphia Inquirer that Howard would return sometime in May. So, the five-time defending NL East champs will play roughly the first month of the season without the 2006 NL MVP, who led the team with 33 homers and 116 RBIs last season.

Prescription: The Phillies won a franchise-record 102 games last season despite second baseman Chase Utley not debuting until May 23, so they have weathered this storm before. Offseason pickup Ty Wiggington and infielder/outfielder John Mayberry should fill in admirably for Howard, and Jim Thome also could start at first base once a week.

Boston Red Sox

Still sore: LF Carl Crawford, who had wrist surgery in January

Recovery time: Few players need to get off to a hot start this season more than Crawford, who was a major disappointment (.255 average, .289 on-base percentage, 18 steals) in his first season with the Red Sox in 2011. But his 2012 season might not begin until late April, as manager Bobby Valentine recently told The Boston Globe he wouldn’t be surprised if Crawford missed the first few weeks of the regular season.

Prescription: Boston already was thin in the outfield, with Ryan Sweeney and Cody Ross expected to platoon in right field. Because of Crawford’s absence, Sweeney and Ross are likely to start. Also in the mix is veteran Darnell McDonald. As long as Crawford isn’t sidelined longer than expected, the Red Sox should be fine offensively. But Sweeney and Ross must adapt quickly to tough defensive assignments in left (Green Monster) and right (plenty of real estate).

Atlanta Braves

Still sore: SP Tim Hudson, who had surgery in November to repair a herniated disk in his back

Recovery time: Braves pitching coach Roger McDowell told The Atlanta Journal-Constitution the team will be cautious with Hudson this spring and won’t rush him back, even hinting that the righthander will be out until mid-April or early May. A better timeline will develop once Hudson, 36, reports to camp and does some throwing.

(UPDATE: Hudson told reporters Sunday that he's targeting early May for his return. He said opening day was never a realistic goal.)

Prescription: If there is one area in which the Braves can flaunt their depth, it is the rotation—even after trading Derek Lowe. Jair Jurrjens (knee) and Tommy Hanson (shoulder) will report to camp healthy after missing all of September and combining to make just 12 second-half starts last season. Youngsters Randall Delgado and Julio Teheran pitched in the majors last season and are capable fill-ins.

San Francisco Giants

Still sore: 2B Freddy Sanchez, who had season-ending surgery to repair a torn labrum in his throwing shoulder last August

Recovery time: Sanchez has been hitting off a tee for more than a month, but throwing will be a tougher challenge. In an interview with MLB.com in January, Sanchez expressed optimism he would be ready to play in Cactus League games but that might be ambitious. In the past three seasons, Sanchez has missed more than 200 games because of various ailments.

Prescription: Only one major league team (Seattle Mariners) finished with fewer runs and a worse on-base percentage last season than San Francisco, which also finished 28th in batting average. A healthy Sanchez, who won the NL batting title in 2006, can help in each of those areas (as can a healthy Buster Posey). Reserve middle infielders Mike Fontenot, Ryan Theriot and Emmanuel Burriss don’t have Sanchez’s upside and might be called upon to play shortstop if young Brandon Crawford falters.